Synchronised swimming seems to make dolphins more optimistic

Bottlenose dolphins that engage in synchronised swimming with their peers tend to see the glass as being half full.

Some of these dolphins frequently swim in tight-knit groups, and they’re the ones who appear the most optimistic, according to a study of eight captive animals.

In the experiment, individual dolphins were trained to swim towards one of two targets. They were taught that when they reach the left one, they receive applause and eye contact, while the one on the right delivers herring – the jackpot – and dolphins swim faster towards it.

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When presented with a new and ambiguous middle target, some dolphins still swim rather fast, presumably hoping they’ll receive another tasty herring, although it’s only a 50/50 chance.

Those were dubbed the “optimistic” dolphins, and the analysis found that they were the same animals who had participated in the most synchronised swimming recently: moving closely alongside their fellow dolphins and matching their movements.

Social swimming

Dolphins continue to make these optimistic judgements up to two months after frequent synchronised swimming with their friends, but the boost fades after that.

Swimming together is an important social activity for dolphins that increases bonding between them, and the researchers argue that it could be linked to positive emotions.

“I think it’s the social behaviour that drives the dolphins’ optimistic decisions,” says Isabella Clegg, a zoologist at the University of Paris-North and lead author of the study. Social interactions are thought to be rewarding and associated with positive views, and she believes her study of synchronised swimming confirms that.

“We know that dolphins in the wild and in captivity tend to use synchronous swimming as a form of bonding, such as between pairs of adult dolphins or mothers and calves,” says Adam Pack, a psychologist at the University of Hawaii at Hilo. “People interpret these behaviours as reinforcing close relationships.”
The dolphins’ optimistic behaviour resembles “cognitive bias”: how humans judge situations differently depending on their social environment. People’s social activity affects their outlook on the world, and something similar may happen among some animals, too.

Kinder zoos

Cognitive bias has been studied with laboratory rats, for example, by comparing those residing in enriched and barren cages. The dolphin study says it is the first test of cognitive bias in a marine mammal or a zoo-housed species.

“This study could be used as a tool to probe aspects of animal welfare in captive environments,” says Lori Marino, a behavioural biologist at Emory University in Atlanta, Georgia. Zoo animals, for instance, don’t choose many aspects of their lives, but they can benefit from opportunities for social activities with their peers, she says.

Clegg agrees. Zookeepers and aquarists could use this to monitor how many dolphins often swim together, and manage their practices accordingly. “In better welfare situations, animals judge [things] more optimistically,” she says.